Extractive Spectrophotometric Methods for the Determination of Enalapril Maleate in Tablets

A simple, rapid, sensitive, precise and economic spectrophotometric method has been developed for the estimation of Enalapril maleate (ENA) in tablet formulation. During the course of study, it was observed that basic solution of the drug formed ion pair complex with Thymolphthaline (THP) which were soluble in chloroform. This property of the drug was followed for the development of colorimetric methods for analysis of drug. The complex of ENA with THP showed λmax at 475 nm. This method was validated statistically. Recovery studies gave satisfactory results indicating that none of common additives and excipients interfere the assay method. The proposed method is found to be simple, accurate and reproducible that was successfully applied for the analysis of tablet formulation.